Electronic camera for producing quickview images

ABSTRACT

An electronic camera according to the present invention includes: an image pickup part for picking up a subject image to produce image data; a processing part for processing the image data outputted from the image pickup part to produce a quickview image for monitor display and also produce image data for record on a recording medium; and a monitor part for displaying the quickview image. The processing part commences displaying the quickview image on the monitor part prior to the production of the image data for record. This processing allows the display of the quickview image to be commenced without waiting for completion of the production of the image data for record. Therefore, it is possible to shorten the time lag occurring at displaying the quickview image, thereby improving the convenience of the electronic camera.

CROSS REFERENCE TO RELATED APPLICATION

[0001] The disclosure of the following priority application is hereinincorporated by reference: Japanese Patent Application No.2001-400744,filed Dec. 28, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an electronic camera thatinternally processes image data obtained by picking up subject images.More particularly, the present invention relates to an electronic camerathat produces image data for record to be recorded on a recording mediumand quickview images for monitor display.

[0004] 2. Description of the Related Art

[0005] In conventional electronic cameras, the following procedures areperformed to process image data.

[0006] 1) Image Capture

[0007] An electronic camera reads image data from its internal imagesensor. The electronic camera implements signal processings on the imagedata, such as A/D conversion, defective pixel correction, opticalblack-level correction, gain adjustment, white balance adjustment, tonecorrection and so on. The signal-processed image data are stored in abuffer memory within the electronic camera.

[0008] 2) Image Processing

[0009] The electronic camera implements image processings on thesignal-processed image data, such as color interpolation, colorcoordinate transformation, color correction, special frequency filteringand so on, and thereby produce image data for record.

[0010] 3) Production of Quickview

[0011] The electronic camera reduces the image size of the image datafor record to produce a quickview image.

[0012] 4) Production and Compression of Thumbnail

[0013] The electronic camera reduces the image size of the image datafor record to generate a thumbnail image for a display list. Theelectronic camera compresses the thumbnail image by use of a hardware orsoftware processing.

[0014] 5) Image Compression

[0015] The electronic camera image-compresses the image data for recordby use of a hardware processing or the like.

[0016] 6) Recording

[0017] The electronic camera implements file recording of theimage-compressed resultants on a recording medium.

[0018] The inventor of the present invention recognizes the followingproblems existent in the above-described processings.

[0019] (1) First Problem

[0020] In general, a user or operator of the electronic camera displaysa quickview image on its monitor screen after capturing a subject image.He or she may use this quickview image on the photo-taking spot todetermine whether the captured result is good or not. It is preferablethat the user or operator can check the quickview without delay at thetime of photographing. It is, therefore, desirable that the quickviewimage be produced as soon as possible after the capturing of the subjectimage.

[0021] In the foregoing example of the prior art, however, the imagesize of the image data for record has to be reduced for generation ofthe quickview image. In such a case, quick generation of the quickviewimage is difficult because there is a need for waiting for a completionof generation of the image data for record.

[0022] For the generation of image data for record, in general, it isnecessary to process full-sized image data. Additionally, in order toimprove the picture quality of the electronic camera, those imageprocessings have to be high-level, complicated processings. This tendsto elongate the time taken for the processings on the image data forrecord, and the generation of the quickview image delays accordingly.

[0023] For the reason above, the above-described example of the priorart is disadvantageous in terms of availability that a time lag islikely to occur from photographing to displaying the quickview image, sothat the user cannot check the captured image smoothly.

[0024] (2) Second Problem

[0025] Reusing the quickview image during image reproduction can shortenthe time required for the image reproduction on the monitor. To preparefor such reuse during image reproduction, it is necessary, when theimage data for record is recorded, to record the quickview imagetogether with the image data for record.

[0026] In the above-described example of the prior art, the electroniccamera must additionally compress and recode the quickview image aftercompleting the image compression of preceding image data for record.This elongates the time required for photographing by a time needed forperforming the additional processings accordingly. Consequently,disadvantages such as a reduction in the speed of a continuous shootingare likely to arise.

SUMMARY OF THE INVENTION

[0027] In view of solving the above-described problems, it is an objectof the present invention to decrease the time lag in displaying thequickview image.

[0028] The present invention will be now described below.

[0029] (1) An electronic camera according to the present inventionincludes: an image pickup part for picking up a subject image to produceimage data; a processing part for processing the image data outputtedfrom the image pickup part to produce a quickview image and image datafor record, the quickview image being used for monitor display, theimage data for record being to be recorded on a recording medium; and amonitor part for displaying the quickview image. The processing partcommences displaying the quickview image on the monitor part before theproduction of the image data for record is completed.

[0030] In this processing, the display of the quickview image iscommenced before the image data for record is generated. Thus, thequickview image can be quickly displayed without waiting for thecompletion of production of the image data for record. As a result, thetime lag occurring at displaying the quickview image can be reduced, sothat the user can review the captured image significantly smoothly.

[0031] (2) More preferably, the processing part of the electronic cameraaccording to the present invention includes an image processing part anda quickview producing part. Upon receiving the image data outputted fromthe image pickup part, the image processing part image-processes theimage data to produce the image data for record. On the other hand, thequickview producing part, upon receiving the image data outputted fromthe image pickup part, reduces the number of the pixels of the imagedata to produce the quickview image, and then commences the display ofthe quickview image before the image data for record is produced.

[0032] In this processing, the quickview image is produced from theoutput of the image pickup part. In such a case, the productionprocessing of the quickview image is almost irreverent of the imageprocessing of the image data for record. This lessens the time lossoccurring due to the processings on the image data for record, therebyenabling quick production of the quickview image. As a result, the timelag occurring at displaying the quickview image can be reduced, so thatthe user can check the captured image significantly smoothly.

[0033] (3) Also preferably, the processing part of the electronic cameraaccording to the present invention includes a buffer part, a reducingpart and an image processing part. The buffer part temporarily storesthe image data outputted from the image pickup part. Upon receiving theimage data from the image pickup part or the buffer part, the reducingpart reduces the number of the pixels of the image data to produceslimmed-down intermediate data (which will be referred to simply as“intermediate data” hereinafter). The image processing part firstlyimage-processes the intermediate data to produce the quickview image andthereafter image-processes the image data temporarily stored in thebuffer part to produce the image data for record.

[0034] The slimmed-down intermediate data are produced first in thisprocessing. Next, the image processing part preferentiallyimage-processes the intermediate data, thereby producing the quickviewimage. The intermediate image can be produced at a high speed because itis produced by a relatively simple processing such as reducing the pixelnumber. Moreover, the production of the quickview image from theintermediate image can be completed at a high speed because the numberof the pixels of the intermediate image to be processed is small. As aresult, the time lag occurring at displaying the quickview image can bedecreased, so that the user can review the captured image significantlysmoothly.

[0035] Furthermore, since the reducing part produces the intermediateimage, the number of the pixels which the image processing partprocesses for production of the quickview image is small, resulting insubstantially lessening the amount of the processings by the imageprocessing part. As a result, the image processing part has a margin toperform other processings in addition to the production processing ofthe quickview image. This margin of the image processing part isefficiently utilized. By utilizing this margin, the image processingpart produces the image data for record after producing the quickviewimage. This eliminates the need to provide any independent imageprocessing parts dedicated to the quickview images and to the image datafor record, thereby simplifying the structure of the electronic camera.

[0036] (4) More preferably, the electronic camera according to thepresent invention further includes an image compressing part and arecording part. The image compressing part first image-compresses thequickview image and the image data for record next to produce theirrespective compressed data. The recording part first records thecompressed data of the quickview image and the compressed data of theimage data for record next.

[0037] According to the processings described above, the quickview imageand image data for record are compressed and recorded in the same orderwhich is the quickview image first, the image data for record second. Insuch a case, it is possible to complete the compression and recording ofa preceding quickview image to some extent before the commencement ofoutputting the image data for record, which can further shortens thetotal processing time.

[0038] (5) Also preferably, the electronic camera according to thepresent invention changes the processings on the image data in thefollowing manner when the image pickup part continuously picks up thesubject image to produce a plurality of sets of image data. That is, thebuffer part temporarily stores the plurality of sets of image data inorder in which the sets of image data are outputted from the imagepickup part. The image processing part reads the image data temporarilystored in the buffer part and produces image data for record. Then, thereducing part reduces the number of the pixels of the image data forrecord to produce quickview images.

[0039] According to the processings described above, in order to performthe continuous shooting, each set of image data for record is producedwith priority to a respective quickview image. Each quickview image isproduced by reducing the number of the pixels of a respective set ofimage data for record. In such a case, every time a set of image datafor record is produced, the buffer part can release the correspondingmemory space. This increases the usage efficiency of the buffer part, bywhich further increases the number of the frames to be continuously shotat one time. In addition, the memory capacity required for the bufferpart may be reduced.

[0040] In the above case, each quickview image is produced later thanits respective set of image data for record. During the continuousshooting, however, the user scarcely checks the quickview images so thatthe delay in producing the quickview images causes no significantproblems.

[0041] It should be noted that in order to perform the continuousshooting, the production of the quickview images may be omitted, or thequickview images may be compressed or recorded after the continuousshooting. In such a case, it is possible to shorten the time required toprocess the image data of each frame, which makes it easier to increasethe speed of the continuous shooting.

[0042] (6) More preferably, the electronic camera according to thepresent invention further includes an image compressing part forimage-compressing the quickview images and the image data for record.When the image pickup part continuously picks up the subject image toproduce the plurality of sets of image data, the electronic cameraimplements the processings as follows. That is, the buffer parttemporarily stores the quickview images which are sequentially producedby the reducing part. The image compressing part receives the quickviewimages from the buffer part to image-compress the quickview images.

[0043] According to the processings described above, the quickviewimages, which are sequentially generated by the continuous shooting, aretemporarily stored in the buffer part. The image compressing partreceives the quickview images from the buffer part to implement imagecompression thereon. Therefore, in a case where the image compressingpart alone performs most of data processings such as in the continuousshooting mode, the quickview images may be compressed at appropriatetimes (by utilizing, for example, free times of the image compressingpart).

[0044] The quickview images are relatively small in content, and henceoccupy small regions of the buffer part. The regions of the buffer partare less occupied when compression is performed at appropriate timesthan when a processing sequence where image data for record are storedin the buffer is performed. This results in easily securing extraneousregions of the buffer part for the buffering in the continuous shootingmode, and in increasing the possible number of frames to be continuouslyshot.

[0045] (7) Also preferably, the electronic camera according to thepresent invention includes an image compressing part forimage-compressing the image data for record to produce compressed datathereof and a recording part for recording the compressed data of theimage data for record. When the image pickup part continuously picks upthe subject image to produce a plurality of sets of image data, theelectronic camera implements processings as follows. That is, the bufferpart temporarily stores the compressed data of the image data for recordwhich are successively produced by the image compressing part. Therecording part receives the compressed data of the image data for recordfrom the buffer part and records them.

[0046] According to the processings described above, during thecontinuous shooting, the compressed data of the image data for recordare temporarily stored in the buffer part. Upon receiving the compresseddata of the image data for record from the buffer part, the recordingpart records them. Therefore, in a case where the image compressing partalone performs most of data processings such as in the continuousshooting mode, the quickview images may be compressed at appropriatetimes (by utilizing, for example, free times of the recording part).

[0047] The regions of the buffer part are less occupied when compressionis performed at appropriate times than when a processing sequence wherenot-yet-compressed image data for record are stored in the buffer isperformed. This results in easily securing extraneous regions of thebuffer part for the buffering in the continuous shooting mode, and inincreasing the possible number of frames to be continuously shot.

[0048] (8) More preferably, the foregoing processing part of theelectronic camera according to the present invention further reduces thenumber of the pixels of the quickview image to produce a thumbnail imagefor a display list.

[0049] According to the processing described above, the pixels of thequickview image are reduced in number to produce the thumbnail image forthe display list. In such a case, processing slimmed-down quickviewimages realizes quick creation of so that the thumbnail image.

[0050] It is particularly preferable that the image compression of thethumbnail image be performed by using image compressing means that isdifferent from the image compressing part (for example, by softwarecompression using an internal microprocessor or the like). This allowsthe image compression of the thumbnail image to be implemented withoutinterfering with the image compressions of the image data for record andof the quickview image.

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The nature, principle, and utility of the invention will becomemore apparent from the following detailed description when read inconjunction with the accompanying drawings in which like parts aredesignated by identical reference numbers, in which:

[0052]FIG. 1 is a block diagram showing the structure of an electroniccamera 1 according to a first embodiment of the present invention.

[0053]FIG. 2 is a timing chart showing operations of the electroniccamera 1.

[0054]FIG. 3 is a block diagram showing the structure of an electroniccamera 11 according to a second embodiment of the present invention.

[0055]FIG. 4 is a diagram showing signal processing paths of theelectronic camera 11 in a single shooting mode.

[0056]FIG. 5 is a timing chart of the electronic camera 11 in the singleshooting mode.

[0057]FIG. 6 is a diagram showing signal processing paths of theelectronic camera 11 in a continuous shooting mode.

[0058]FIG. 7 is a timing chart of the electronic camera 11 in thecontinuous shooting mode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0059] Embodiments of the present invention will be described below withreference to the drawings.

[0060] <FIRST EMBODIMENT>

[0061]FIG. 1 is a block diagram showing the structure of an electroniccamera 1 according to a first embodiment of the present invention. Thestructure of the electronic camera 1 will be described below withreference to FIG. 1.

[0062] The electronic camera 1 has lenses 2 mounted thereon, and alsohas an image sensor 3 whose image plane is located in the image space ofthe lenses 2. An output of the image sensor 3 is supplied through an A/Dconverting part 4 to a signal processing part 5, an output of which issupplied to an image processing part 6 and also supplied to a quickviewproducing part 7.

[0063] The image processing part 6 implements image processings on theoutput supplied from the signal processing part 5 to produce image datafor record, which are then supplied to an image compressing part 8.

[0064] On the other hand, the quickview producing part 7 produces aquickview image based on the output supplied from the signal processingpart 5. The quickview image is supplied to the image compressing part 8,and also supplied to a monitor display part 7 a and displayed thereonfor monitoring. The quickview producing part 7 also produces a thumbnailimage that is small in image size. The thumbnail image is outputted to athumbnail compressing part 9.

[0065] The image compressing part 8 image-compresses the quickview imagefirst and image data for record next to output their respectivecompressed data to a recording part 10. Meanwhile, the thumbnailcompressing part 9 implements image compression of the thumbnail imageto output the compressed data thereof to the recording part 10. Therecording part 10 records these compressed data onto a recording mediumsuch as a memory card or the like.

[0066] [Relation between the Invention and the Present Embodiment]

[0067] The relations between the invention and the present embodimentwill be described below. It, however, should be noted that suchcorrespondence is intended to show an example of interpretation just forreference sake and is not intended to limit the present invention.

[0068] The image pickup part recited in the Claims corresponds to theimage sensor 3, A/D converting part 4 and signal processing part 5.

[0069] The processing part recited in the Claims corresponds to theimage processing part 6 and quickview producing part 7.

[0070] The monitor part recited in the Claims corresponds to the monitordisplay part 7 a.

[0071] The image processing part recited in the Claims corresponds tothe image processing part 6.

[0072] The quickview producing part recited in the Claims corresponds tothe quickview producing part 7.

[0073] The image compressing part recited in the Claims corresponds tothe image compressing part 8.

[0074] The recording part recited in the Claims corresponds to therecording part 10.

[0075] [Explanation of Operations of the First Embodiment]

[0076]FIG. 2 is a timing chart showing operations of the electroniccamera 1.

[0077] The operations of the electronic camera 1 will be explained belowwith reference to FIG. 2.

[0078] (1) Exposure

[0079] The lenses 2 focus a subject image onto the image plane of theimage sensor 3. The image plane of the image sensor 3 includes a colorfilter array of a Bayer pattern or the like, which provides opticalcolor separation of the subject image. The image sensor 3 implementsphotoelectric conversion of the thus separated color components (RGB orthe like) pixel by pixel, and stores them as signal charges.

[0080] (2) Scan/Read

[0081] The image sensor 3 stores the signal charges for a predeterminedexposure time period under a known electronic shutter control or with amechanical shutter. Thereafter, the image sensor 3 outputs an imagesignal in accordance with a driving pulse supplied from a timinggenerator (not shown). The A/D converting part 4 A/D converts the imagesignal in real time to output digital image data.

[0082] (3) Signal Processing

[0083] The digital converted image data are inputted to the signalprocessing part 5, which executes processings on the image data in realtime, such as defective pixel correction, optical black-levelcorrection, gain correction, white balance correction, gamma correctionand so on.

[0084] (4) Production of Image Data for Record

[0085] The image processing part 6 sequentially receives thereal-time-processed image data from the signal processing part 5, andimplements image processings on the image data, such as colorinterpolation processing, color correction processing, filter processingand so on, thereby producing image data for record. The image data forrecord are temporarily stored in an image memory (not shown) within theimage processing part 6.

[0086] (5) Production of quickview Image and Production of ThumbnailImage

[0087] The quickview producing part 7 sequentially receives thereal-time-processed image data from the signal processing part 5. Thequickview producing part 7 equally partitions the pixel pattern of theimage data in accordance with the numbers of the vertical and horizontalpixels of a quickview image to be produced, thereby providing pixelblocks that are equal in number to the pixels of the quickview image.The quickview producing part 7 averages each sort of color components ineach of the pixel blocks to provide the signal components of thequickview image. The monitor display part 7 a displays the quickviewimage for monitoring. A user or operator can quickly review the lastpicked-up or captured image by viewing this monitor display.

[0088] It should be appreciated that a quickview image may be producedby thinning out the image data.

[0089] The quickview producing part 7 thins out the pixels of theproduced quickview image, thereby further reducing the image size toproduce a thumbnail image for a display list.

[0090] The productions of the quickview and thumbnail images describedabove are simple in operation and deal with small amounts of data ascompared with the foregoing production of the image data for record.Therefore, the quickview and thumbnail images are generated earlier thanthe image data for record. Consequently, the earlier generated quickviewimage is outputted prior to the image data for record.

[0091] It should be noted that the foregoing “Production of quickviewImage” and “Production of Thumbnail Image” are preferably implemented ina pipeline fashion.

[0092] (6) Thumbnail Compression

[0093] The thumbnail compressing part 9 receives the thumbnail imagefrom the quickview producing part 7 and implements image compressionthereof. The small compressed data are temporality held within thethumbnail compressing part 9 and outputted to the recording part 10 at atime when the recording part 10 is ready for recording.

[0094] (7) quickview Compression

[0095] The image compressing part 8 receives the quickview image fromthe quickview producing part 7 and implements image compression thereof.

[0096] (8) Recording of quickview Compressed Data

[0097] The recording part 10 receives the compressed data of thequickview image from the image compressing part 8 and sequentiallyrecords them.

[0098] (9) Compression of Image Data for Record

[0099] The image compressing part 8 receives, after completing the imagecompression of the quickview image, the image data for record from theimage processing part 6, and implements image compression thereof.

[0100] (10) Recording of Compressed Data of Thumbnail Images

[0101] The recording part 10 receives, after completing the recording ofthe compressed data of the quickview images, the compressed data of thethumbnail images from the thumbnail compressing part 9, and records themin sequence.

[0102] (11) Recording of Compressed Data of Image Data for Record

[0103] The recording part 10 receives, after completing the recording ofthe compressed data of the thumbnail image, the compressed data of theimage data for record from the image compressing part 8, andsequentially records them.

[0104] The series of operations explained above completes the imagingprocedure of the electronic camera 1.

[0105] [Advantages of the First Embodiment]

[0106] As described above, in the first embodiment, the outputting ofthe quickview image is commenced prior to that of the image data forrecord. Therefore, the quickview image can be quickly displayed, so thatthe user can review the captured image quite smoothly.

[0107] Particularly, in the first embodiment, the quickview producingpart 7 directly receives the image data from the signal processing part5 to produce the quickview image. This allows the production of thequickview image to be commenced quickly without waiting for a completionof the time-consuming processings implemented by the image processingpart 6. As a result, the time lag occurring at displaying the quickviewimage can be significantly reduced.

[0108] Besides, in the first embodiment, the production of the quickviewimage and that of the image data for record are performed in parallel.In this case, it is advantageous that the production of the image datafor record does not delay since the production of the image data forrecord starts nearly at the same time as that of the quickview image.

[0109] Additionally, in the first embodiment, the outputting of thequickview image and that of the image data for record are commenced inthe order named. The image compressing part 8 implements imagecompressions on them in this order. This allows the image compression ofthe quickview image to advance to some degree in parallel with theproduction of the image data for record, so that the whole processingtime can be efficiently shortened.

[0110] Furthermore, in the first embodiment, the compressed data of thequickview image and that of the image data for record are produced inthe order named. The recording part 10 implements the recordings of thecompressed data in this order. This allows the recording of thecompressed data of the quickview image to advance to some degree inparallel with the production of the image data for record, so that thewhole processing time can be efficiently shortened.

[0111] Also, in the first embodiment, the quickview image is processedto produce the thumbnail image. In this case, only the slimmed-downquickview image needs to be processed, which enables quick production ofthe thumbnail image through a simple processing.

[0112] Next, another embodiment will be described below.

[0113] <Second Embodiment>

[0114]FIG. 3 is a block diagram showing the structure of an electroniccamera 11 according to a second embodiment. FIG. 3 shows a control IC 99surrounded with dashed lines. The signal processing system of theelectronic camera 11 is constituted of the control IC 99 and peripheralcomponents.

[0115] The structure of the electronic camera 11 will be described belowin detail.

[0116] The electronic camera 11 has a lens 12 mounted thereon, and alsohas an image sensor 13 whose image plane is located in the image spaceof the lens 12. Image data outputted from the image sensor 13 aresupplied to an A/D converting part 14 to be digitalized thereby. Thedigitalized image data are then inputted to a signal processing engine99 a.

[0117] The signal processing engine 99 a is constituted of processingblocks a signal processing part 15, a thinning part 16, an imageprocessing part 17, a resolution converting part 18, an imagecompressing part 19 and so on. These processing blocks 15 through 19 areconnected with one another via direct signal paths and via a picture bus20.

[0118] A video controller 31, a video encoder 32 and so on are alsoconnected to the picture bus 20 via a FIFO 30. A video signal outputtedfrom the video encoder 32 is displayed on a liquid crystal monitor 32 aprovided on the back surface of the electronic camera 11.

[0119] The picture bus 20 is also connected to a system bus 24 and to anexternal bus 25 via bus interfaces 21 and 22 that switch busconnections. These bus interfaces 21 and 22 are controlled by amicroprocessor 50 that will be described later.

[0120] The external bus 25 is connected to external components: a SDRAM(synchronous DRAM) 26, a ROM 27, an I/O device 28 and so on. In order toproduce a control signal for the SDRAM 26, an SDRAM controller 26 a isprovided in the control IC 99. In order to realize a DMA (direct memoryaccess) transfer without intervention of the microprocessor 50 that willbe described later, a DMA controller 26 b is also provided in thecontrol IC 99.

[0121] On the other hand, the system bus 24 is connected to a serialport 41, a USB (Universal Serial Bus) 42 and a card interface 43. Portterminals of the serial port 41 are extended to the exterior to thecontrol IC 99 and connected to an audio LSI 45, a timing generator 44that drives the image sensor 13, and so on. A terminal of the USB 42 isalso extended to the exterior to the control IC 99 and may be connectedto an external host computer 46 if necessary. The card interface 43writes data into a memory card 47 for data storage.

[0122] The control IC 99 also incorporates the microprocessor 50 forsystem control. The microprocessor 50 is constituted of a data cache 51,a RISC (Reduced Instruction Set Computer) core 52 that is an instructionexecuting unit, and an instruction cache 53.

[0123] [Correspondence between the Invention and the Present Embodiment]

[0124] The correspondence between the invention and the presentembodiment will be described below. It, however, should be noted thatsuch correspondence is intended to show an example of interpretationjust for reference sake and is not intended to limit the presentinvention.

[0125] The image pickup part recited in the Claims corresponds to theimage sensor 13, A/D converting part 14 and signal processing part 15.

[0126] The processing part recited in the Claims corresponds to thethinning part 16, image processing part 17, resolution converting part18, image compressing part 19, video controller 31 and microprocessor50.

[0127] The monitor part recited in the Claims corresponds to the liquidcrystal monitor 32 a.

[0128] The buffer part recited in the Claims corresponds to the SDRAM26.

[0129] The reducing part recited in the Claims corresponds to thethinning part 16 and resolution converting part 18.

[0130] The image processing part recited in the Claims corresponds tothe image processing part 17.

[0131] The image compressing part recited in the Claims corresponds tothe image compressing part 19.

[0132] The recording part recited in the Claims corresponds to the cardinterface 43 and microprocessor 50.

[0133] [Explanation of Operation of Single Shooting]

[0134] The electronic camera 11 described above has two shooting modes:a single shooting mode and a continuous shooting mode. An operation ofthe single shooting mode will be explained below first.

[0135]FIG. 4 is a diagram showing signal processing paths of theelectronic camera 11 in the single shooting mode.

[0136]FIG. 5 is a timing chart of the electronic camera 11 in the singleshooting mode.

[0137] The operation of the single shooting mode will be now explainedbelow with reference to FIGS. 3 through 5.

[0138] (1) Exposure

[0139] The image plane of the image sensor 13 includes a color filterarray of a Bayer pattern or the like. The image sensor 13 performs,pixel by pixel, photoelectric conversion on color-separated lightsthrough the color filter array, and stores them as signal charges.

[0140] (2) Scan/Read

[0141] The image sensor 13 stores the signal charges for a predeterminedexposure time period, and thereafter outputs an image signal inaccordance with a driving pulse supplied from the timing generator 44.The A/D converting part 14 A/D converts the image signal in real time tooutput digital image data.

[0142] (3) Signal Processing

[0143] The digital-converted image data are inputted to the signalprocessing part 15, which performing processings on those image data-inreal time, such as defective pixel correction, optical black-level (OB)correction, gain adjustment, white balance (WB) adjustment, gammacorrection and so on.

[0144] (4) Buffer Storage

[0145] The image data outputted in real time from the signal processingpart 15 are supplied to the thinning part 16, while they are temporarilystored in the SDRAM 26 via the picture bus 20 and external bus 25.

[0146] (5) Reduction

[0147] The thinning part 16 sequentially receives image data outputtedin real time by the signal processing part 15. The thinning part 16implements pixel number reduction (pixel thinning, pixel averaging orthe like) on the image data to produce intermediate data in which thepixels have been reduced in number.

[0148] In the view of performing consistent processing, it is preferablethat the intermediate data be subjected to a color interpolationequivalent to the color interpolation of image data for record that willbe described later. Therefore, the thinning part 16 of the presentembodiment implements pixel number reduction such that the color patternof the image data and that of the intermediate data will coincide witheach other.

[0149] In a case where the image sensor 13 is of interlace system, theimage data of the first field are temporarily stored in the SDRAM 26,and subsequently the image data of the second field are outputted fromthe signal processing part 15. At this moment, the thinning part 16preferably implements pixel number reduction each time a predeterminedunit of data becomes available for the pixel number reduction.

[0150] (6) Image Processing of Intermediate Data

[0151] The image processing part 17 sequentially receives theintermediate data from the thinning part 16. The image processing part17 sequentially implements the color interpolation processing, colorcorrection processing and filter processing on the intermediate data.

[0152] (7) Resolution Adjustment of quickview Image and Production ofThumbnail Image

[0153] The resolution converting part 18 receives the intermediate dataimage-processed by the image processing part 17. The resolutionconverting part 18 implements resolution conversion of theimage-processed intermediate data to produce a quickview Image that hasbeen adjusted in image size in accordance with the monitor resolution.

[0154] It should be noted that when the intermediate data and thequickview Image are equal to each other in resolution, the resolutionconversion thereon is omitted.

[0155] The video controller 31 uses the SDRAM 26 or the like as a videomemory to cause the quickview Image to be monitor-displayed. The usermay view this monitor display to quickly review the last captured image.

[0156] Furthermore, the resolution converting part 18 reduces the numberof the pixels of the produced quickview image to produce a thumbnailimage for a display list.

[0157] (8) Compression of Thumbnail

[0158] The microprocessor 50 receives the thumbnail image from theresolution converting part 18 to implement compression of the thumbnailimage based on a software processing. The compressed data of thethumbnail image are transferred to the SDRAM 26 to be temporarily storedtherein.

[0159] It should be appreciated that the microprocessor 50 may use theSDRAM 26 as an input buffer to receive the thumbnail image. In such acase, the microprocessor 50 may receive the thumbnail image from theSDRAM 26 to implement the compression thereon independently of thetiming at which the thumbnail image is produced by the resolutionconverting part 18. As a result, the microprocessor 50 may efficientlyimplement the compression on the thumbnail image, for example, during aninterval between system controls such as switch monitoring and the like.

[0160] (9) Compression of quickview

[0161] The image compressing part 19 receives the quickview Image fromthe resolution converting part 18 to implement the image compressionthereof. The image compressing part 19 transfers the compressed data ofthe quickview Image to the SDRAM 26, which temporarily stores themtherein.

[0162] It should be noted that the foregoing “Compression of Thumbnail”and “Compression of quickview” are preferably implemented in parallel.

[0163] (10) Recording of Compressed Data of quickview

[0164] The microprocessor 50 (or DMA controller 26 b) derives thecompressed data of the quickview image from the SDRAM 26, and transfersthem to the card interface 43 to sequentially record them in the memorycard 47.

[0165] (11) Recording of Compressed Data of Thumbnail Image

[0166] After completing recording of the compressed data of thequickview image, the microprocessor 50 (or DMA controller 26 b) derivesthe compressed data of the thumbnail image from the SDRAM 26, andtransfers them to the card interface 43, which sequentially records themin the memory card 47.

[0167] (12) Production of Image Data for Record

[0168] After completing the image processings on the intermediate data,the image processing part 17 reads the image data buffer-stored in theSDRAM 26. The image processing part 17 then implements image processingson the image data, such as color interpolation processing, colorcorrection processing, filter processing and so on, to produce the imagedata for record.

[0169] (13) Compression of Image Data for Record

[0170] After completing the image compression of the quickview image,the image compressing part 19 receives the image data for record fromthe image processing part 17 to implement image compression thereof. Theimage compressing part 19 transfers the compressed data of the imagedata for record to the SDRAM 26, which temporarily stores them therein.

[0171] (14) Recording of Compressed Data of Image Data for Record

[0172] The microprocessor 50 (or DMA controller 26 b) derives thecompressed data of the image data for record from the SDRAM 26, andtransfers them to the card interface 43 to sequentially record them inthe memory card 47.

[0173] The series of operations explained above completes the operationof the single shooting mode.

[0174] [Explanation of Operation of Continuous Shooting]

[0175] Next, an operation of the continuous shooting mode will beexplained below.

[0176]FIG. 6 is a diagram showing signal processing paths of theelectronic camera 11 in the continuous shooting mode.

[0177]FIG. 7 is a timing chart of the electronic camera 11 in thecontinuous shooting mode.

[0178] The operation of the continuous shooting mode will be nowexplained below with reference to FIGS. 3, 6 and 7.

[0179] (1) Exposure and Scan/Read

[0180] With its shutter release button (not shown) being pressed on, theelectronic camera 11 continuously exposes and scans/reads the imagesensor 13.

[0181] (2) Signal Processing

[0182] The signal processing part 15 implements processings in real timeon the data of the images continuously picked up, such as defectivepixel correction, optical black-level (OB) correction, gain adjustment,white balance adjustment, gamma correction and so on.

[0183] (3) Buffer Storage

[0184] The image data continuously outputted from the signal processingpart 15 are supplied through the picture bus 20 and external bus 25 tothe SDRAM 26 to be sequentially stored in continuous shooting bufferregions of the SDRAM 26.

[0185] (4) Production of Image Data for Record

[0186] The image processing part 17 reads the image data from thecontinuous shooting buffer regions of the SDRAM 26 in the picking-uporder. The image processing part 17 then implements image processings onthe image data, such as color interpolation processing, color correctionprocessing, filter processing and so on, to produce the image data forrecord. It should be noted that in order to increase the number of theframes to be continuously shot at one time, the continuous shootingbuffer regions from which the image data have been read for those imageprocessings are immediately released and become usable as the latestcontinuous shooting buffer regions.

[0187] It also should be noted that in a case where the image sensor 13is of interlace system, the image data of the first field aretemporarily stored in the SDRAM 26, and subsequently the image data ofthe second field are outputted from the signal processing part 15. Atthis moment, the image processing part 17 preferably implements theabove described image processings each time a predetermined unit of databecomes available for those image processings.

[0188] It also should be noted that in a case where the image sensor 13is of progressive system, it may receive the image data directly fromthe signal processing part 15 as long as the image processing part 17has no delay in processings.

[0189] (5) Compression of Image Data for Record

[0190] The image compressing part 19 receives the image data for recordfrom the image processing part 17 to implement image compressionthereof. The image compressing part 19 transfers the compressed data ofthe image data for record to the SDRAM 26, which temporarily stores themtherein.

[0191] (6) Recording of Compressed Data of Image Data for Record

[0192] The microprocessor 50 (or DMA controller 26 b) derives thecompressed data of the image data for record from the SDRAM 26, andtransfers them to the card interface 43 to sequentially record them inthe memory card 47.

[0193] (7) Production of quickview Image

[0194] The resolution converting part 18 receives the image data forrecord from the image processing part 17, and implements resolutionconversion of the image data for record to produce a quickview Image,which is then transferred to the SDRAM 26 and temporarily stored in theprocessing buffer regions thereof.

[0195] (8) Production of Thumbnail Image

[0196] The thinning part 16 receives the quickview image from theresolution converting part 18, and implements pixel number reduction(pixel thinning, pixel averaging or the like) of the quickview image toproduce a thumbnail image for a display list.

[0197] It should be noted that the foregoing “Production of quickviewImage” and “Production of Thumbnail Image” are preferably implemented ina pipeline fashion.

[0198] (9) Compression of Thumbnail

[0199] The microprocessor 50 sequentially receives the thumbnail imagefrom the thinning part 16 to implement image compression thereof basedon a software processing. The microprocessor 50 (or DMA controller 26 b)transfers the compressed data of the thumbnail image to the SDRAM 26,which temporarily stores them therein.

[0200] It should be appreciated that the microprocessor 50 may use theSDRAM 26 as an input buffer to receive the thumbnail image. In such acase, the microprocessor 50 may receive the thumbnail image from theSDRAM 26 to implement the compression thereof, independently of thetiming at which the thumbnail image is produced by the resolutionconverting part 18. As a result, microprocessor 50 may efficientlyimplement the compression of the thumbnail image, for example, during aninterval between system controls such as a switch monitoring and thelike.

[0201] (10) Compression of quickview Image

[0202] The image compressing part 19, after completing the imagecompression of the image data for record, reads the quickview Image fromthe SDRAM 26 to implement the image compression thereof. The imagecompressing part 19 transfers the compressed data of the quickview Imageto the SDRAM 26, which temporarily stores them therein.

[0203] (11) Recording of Compressed Data of Thumbnail and quickviewImages

[0204] After completing the recording of the compressed data of theimage data for record, the microprocessor 50 (or DMA controller 26 b)derives the compressed data of the thumbnail image from the SDRAM 26,and transfers them to the card interface 43, which records them in thememory card 47.

[0205] After completing the recording of the compressed data of thethumbnail image, the microprocessor 50 (or DMA controller 26 b) derivesthe compressed data of the quickview image from the SDRAM 26, andtransfers them to the card interface 43, which records them in thememory card 47.

[0206] The series of operations explained above completes the continuousshooting mode.

[0207] [Advantages of Second Embodiment]

[0208] As explained above, in the single shooting mode, the outputtingof the quickview image is commenced prior to that of the image data forrecord. Therefore, the quickview image can be quickly displayed, so thatthe user can review the captured image quite smoothly.

[0209] Especially, when producing the quickview image, the electroniccamera 11 produces first the intermediate data where the number of thepixels has been reduced. As a result, the electronic camera 11 onlyneeds to implement image processings on the slimmed-down intermediatedata so as to produce the quickview image. Thus, the quickview image canbe quickly completed.

[0210] Besides, in the single shooting mode, the quickview image and theimage data for record are generated at different timings from eachother. Therefore, using the single image processing part 17 thequickview image and image data for record are smoothly image-processed.This eliminates the necessity for providing separate image processingparts respectively dedicated to the quickview image and the image datafor record. As a result, the structure of the electronic camera 11 issimplified.

[0211] Also, in the single shooting mode, the outputting of thequickview image and that of the image data for record are commenced inthe order named. The image compressing part 19 implements imagecompression on them in this order. Therefore, the quickview image can becompressed to some degree in parallel with the production of the imagedata for record. As a result, the whole processing time can beefficiently shortened.

[0212] Furthermore, in the single shooting mode, the compressed data ofthe quickview image and that of the image data for record are producedin the order named. The card interface 43 records their compressed datain this order. Therefore, while the image data for record are beingproduced, the recording of the compressed data of the quickview imagecan be advanced to some degree. As a result, the whole processing timecan be efficiently shortened.

[0213] On the other hand, in the continuous shooting mode, the imagedata for record is preferentially generated, and the quickview imagesare generated by processing the image data for record. Thus, the imagedata for record are generated earlier, whereby the continuous shootingbuffer regions of the SDRAM 26 can be released quickly one afteranother, resulting in increasing the possible number of frames in thecontinuous shooting.

[0214] As described above, in the second embodiment, the operations (6)through (11) indicated below are performed for each frame in thecontinuous shooting.

[0215] (6) Recording of compressed data of image data for record

[0216] (7) Production of quickview image

[0217] (8) Production of thumbnail image

[0218] (9) Compression of thumbnail

[0219] (10) Compression of quickview image

[0220] (11) Recording of compressed data of thumbnail and quickviewimages

[0221] It, however, should be noted that all or a part of theseoperations (6) through (11) may be implemented after the end of thecontinuous shooting. In such a case, the time required for each exposurein the continuous shooting mode can be shortened, so that the speed ofthe continuous shooting can be significantly increased.

[0222] Especially, performing the operations (6), (10) and (11) afterthe continuous shooting can further increase the speed of the continuousshooting because these operations are time-consuming. (This is becausethe quickview images cannot be compressed during compression of theimage data for record so that these three operations are likely to haveto be sequential.) On the other hand, since the operations (7), (8) and(9) can be implemented concurrently with the compression of the imagedata for record, performing these operations (7), (8) and (9) for eachframe will not significantly reduce the speed of the continuousshooting. In a case where the control operation of the MPU 50 is slow,however, it is preferable that the operation (9) be implemented afterthe completion of the continuous shooting so as not to reduce the speedof the continuous shooting.

[0223] In the second embodiment, the processing sequences are differentbetween the single and continuous shootings. Consequently, the quickviewimage can be quickly displayed at the time of the single shooting, whilethe speed of the continuous shooting can be increased in the continuousshooting. However, the present invention is not limited thereto. Forexample, the above-described processing sequence of the continuousshooting mode may be performed in the single shooting mode.

[0224] The invention is not limited to the above embodiments and variousmodifications may be made without departing from the spirit and scope ofthe invention. Any improvement may be made in part or all of thecomponents.

What is claimed is:
 1. An electronic camera comprising: an image pickuppart for picking up a subject image to produce image data; a processingpart for processing said image data outputted from said image pickuppart to produce a quickview image and image data for record, thequickview image being used for monitor display, the image data forrecord being to be recorded on a recording medium; and a monitor partfor displaying said quickview image, wherein said processing partcommences displaying said quickview image on said monitor part prior toa completion of production of said image data for record.
 2. Theelectronic camera according to claim 1, wherein said processing partcomprises: an image processing part for receiving said image dataoutputted from said image pickup part to image-process said image dataand produce said image data for record; and a quickview producing partfor receiving said image data outputted from said image pickup part toreduce the number of pixels of said image data and to thereby producesaid quickview image, and for commencing displaying said quickview imageon said monitor part prior to the completion of production of said imagedata for record.
 3. The electronic camera according to claim 1, whereinsaid processing part comprises: a buffer part for temporarily storingsaid image data outputted from said image pickup part; a reducing partfor receiving said image data from one of said image pickup part andsaid buffer part to reduce the number of pixels of said image data andto thereby produce slimmed-down intermediate data; and an imageprocessing part for producing said quickview image first byimage-processing said intermediate data outputted from said reducingpart and for producing said image data for record second byimage-processing said image data temporarily stored in said buffer part.4. The electronic camera according to claim 1, further comprising: animage compressing part for compressing said quickview image first andsaid image data for record second to produce their respective compresseddata; and a recording part for recording the compressed data of saidquickview image first and the compressed data of said produced imagedata for record second.
 5. The electronic camera according to claim 3,wherein when said image pickup part produces a plurality of sets ofimage data by continuously picking up a subject image, said buffer partsequentially and temporarily stores said plurality of sets of image dataoutputted from said image pickup part, said image processing part readssaid image data temporarily stored in said buffer part and produces saidimage data for record, and said reducing part reduces the number ofpixels of said image data for record to produce said quickview images insequence.
 6. The electronic camera according to claim 5, furthercomprising an image compressing part for compressing said quickviewimage and said image data for record, wherein when said image pickuppart produces the plurality of sets of image data by continuouslypicking up the subject image, said buffer part temporarily stores saidquickview images sequentially produced by said reducing part, and saidimage compressing part receives said quickview images from said bufferpart to compress said quickview images.
 7. The electronic cameraaccording to claim 5, further comprising: an image compressing part forsequentially compressing said image data for record to producecompressed data thereof; and a recording part for recording thecompressed data of image data for record sequentially produced by saidimage compressing part, wherein when said image pickup part produces aplurality of sets of image data by continuously picking up a subjectimage, said buffer part temporarily stores the compressed data of saidimage data for record sequentially produced by said image compressingpart, and said recording part receives the compressed data of said imagedata for record from said buffer part and records the receivedcompressed data of said image data for record.
 8. The electronic cameraaccording to claim 1, wherein said processing part reduces the number ofpixels of said quickview image to produce a thumbnail image for adisplay list.